| Description | Date | Identifier | |
| Piston breakage on a 20 HP chassis and proposing design modifications to the piston rings. | 7th Jul 1928 | Box 16 \ 1 Scan202 | |
| Development and testing of improved piston designs for 20 HP and Phantom engines. | 20th Jul 1928 | Box 16 \ 1 Scan203 | |
| From Royce expressing anxiety about piston rings and suggesting design changes for the Twenty HP and Phantom models. | 23th Jul 1928 | Box 16 \ 1 Scan204 | |
| Modifications to Phantom piston rings to increase cylinder wall pressure. | 23th Jul 1928 | Box 16 \ 1 Scan205 | |
| Design, testing, and grinding instructions for a new pedestal piston. | 24th Jul 1928 | Box 16 \ 1 Scan206 | |
| Fitting of pistons and rings for 20 HP and Phantom engines. | 1st Jul 1928 | Box 16 \ 1 Scan207 | |
| Performance of 'perfect circle' versus 'L' shaped piston rings and the number of rings per piston. | 1st Aug 1928 | Box 16 \ 1 Scan208 | |
| Performance of cross web pistons and 4 pinned rings on a 20 HP car. | 9th Sep 1928 | Box 16 \ 1 Scan209 | |
| Consideration of piston rings from the Wellworthy Piston Ring company. | 3rd Oct 1928 | Box 16 \ 1 Scan210 | |
| Letter from a Managing Director discussing the benefits and trial of a new slotted oil control piston ring. | 1st Oct 1928 | Box 16 \ 1 Scan211 | |
| Submitted type of piston ring already being used for aero work. | 4th Oct 1928 | Box 16 \ 1 Scan212 | |
| Design and specifications of pistons and piston rings. | 18th Oct 1928 | Box 16 \ 1 Scan213 | |
| Desired specifications and features for pistons on Phantom and 20 HP models. | 30th Jan 1929 | Box 16 \ 1 Scan214 | |
| Oil-controlled piston ring sample submitted by the Light Production Company. | 30th Jan 1929 | Box 16 \ 1 Scan215 | |
| Use of rectangular piston rings on the SS chassis and monitoring for over-oiling. | 17th Jan 1929 | Box 16 \ 1 Scan216 | |
| Letter from The Light Production Co. Ltd. describing their new 'Slotted Wypa' Oil Control Ring. | 28th Jan 1929 | Box 16 \ 1 Scan217 | |
| Letter from The Light Production Company Limited regarding scraper and piston rings. | 28th Jan 1929 | Box 16 \ 1 Scan218 | |
| Oil control and efficiency, quoting a letter from Wellworthy Limited about their new 'High Efficiency' Slotted Oil Control Piston Ring. | 11th Apr 1933 | Box 16 \ 1 Scan219 | |
| Tendency for piston rings to collapse at high speeds and requesting crankcase pressure data. | 19th Jun 1933 | Box 16 \ 1 Scan220 | |
| Standardisation of chassis parts concerning turbulent flow radiator tubes. | 18th Oct 1930 | Box 16 \ 2 Scan001 | |
| Standardisation of a shallow tank radiator, wider dashboard, and overlapping bonnet to improve the appearance of the car. | 24th Jul 1930 | Box 16 \ 2 Scan002 | |
| Graph comparing stabilised engine water temperature against car speed for bonnets with vertical and horizontal louvres. | 24th Jul 1930 | Box 16 \ 2 Scan003 | |
| Page of various numerical calculations and jottings. | 11th Feb 1931 | Box 16 \ 2 Scan004 | |
| Test results for a 'J' Filling Thermostat, detailing opening and closing temperatures. | 11th Feb 1931 | Box 16 \ 2 Scan005 | |
| Modifications to a radiator cap to prevent bursting radiators. | 11th Apr 1931 | Box 16 \ 2 Scan006 | |
| The first series of tests comparing different radiator tube designs for the Phantom II model. | 21th Apr 1931 | Box 16 \ 2 Scan007 | |
| Report page discussing the efficiency and cost of a tube shape, pending further tests. | 21th Apr 1931 | Box 16 \ 2 Scan008 | |
| Comparative table of radiator tube performance based on critical air temperature tests. | 21th Apr 1931 | Box 16 \ 2 Scan009 | |
| Technical drawing for a 'Matrix Tube' with specifications for annealing and pressure testing. | 21th Apr 1931 | Box 16 \ 2 Scan010 | |
| Instruction to fit a modified anti-splash radiator cap to specific experimental cars. | 22th Apr 1931 | Box 16 \ 2 Scan011 | |
| Water flow test results for an SS.15 unit, comparing four different radiator configurations. | 21th Apr 1931 | Box 16 \ 2 Scan012 | |
| Comparative table of radiator types and their boiling temperatures at specified speeds. | 21th Apr 1931 | Box 16 \ 2 Scan013 | |
| Table showing the boiling temperatures in Celsius for different types of bonnet ventilation at various speeds. | 19th Aug 1921 | Box 16 \ 2 Scan014 | |
| Graph comparing water pump delivery and suction/pressure performance for three different radiator types against engine RPM. | 19th Aug 1921 | Box 16 \ 2 Scan015 | |
| Comparison table of different radiator matrix types and their boiling temperatures under various conditions. | 21th Apr 1931 | Box 16 \ 2 Scan016 | |
| Page with a purple 'Print Room' stamp in the bottom right corner. | 28th May 1931 | Box 16 \ 2 Scan017 | |
| Note indicating that for photostats, the original document should be consulted. | 19th May 1931 | Box 16 \ 2 Scan018 | |
| Replacement of a faulty radiator anti-splash valve to prevent radiators bursting. | 21th May 1931 | Box 16 \ 2 Scan019 | |
| Radiator improvements for 45 HP and 25 HP models, including changes to copper tubes, weight reduction, and non-spilling valves. | 22th May 1931 | Box 16 \ 2 Scan020 | |
| Experimental order for radiator tubes for 40/50 HP and 20/25 HP models. | 27th May 1931 | Box 16 \ 2 Scan021 | |
| Test report on bonnet rattles, water temperature, steering improvements, and petrol boiling issues. | 29th Jun 1931 | Box 16 \ 2 Scan022 | |
| Performance of different radiator types for Phantom II Cooling. | 8th Jul 1931 | Box 16 \ 2 Scan023 | |
| Comparative tests on different radiator tube sizes and their impact on engine cooling. | 18th Jul 1931 | Box 16 \ 2 Scan024 | |
| Standardisation of large diameter American tubes for radiators for the 25 HP and 40/50 models. | 23th Jul 1931 | Box 16 \ 2 Scan025 | |
| Summary of Phantom II radiator tests conducted in France, detailing temperature rises during a hill climb. | 7th Aug 1931 | Box 16 \ 2 Scan026 | |
| Summary of radiator tests comparing critical atmospheric temperatures with and without bonnet ventilation at various speeds and conditions. | 1st Jan 1931 | Box 16 \ 2 Scan027 | |
| Summary of radiator performance tests conducted in France, comparing small and large dented hexagon radiators. | 1st Aug 1931 | Box 16 \ 2 Scan028 | |
| Replacement large diameter American Type Matrix Tube for the Phantom II chassis radiator. | 13th Aug 1931 | Box 16 \ 2 Scan029 | |
| Letter detailing blueprints for the Phantom II radiator mounting and other modifications. | 20th Aug 1931 | Box 16 \ 2 Scan030 | |
| Radiator requirements for the 27-EX and bumper chassis models. | 21th Aug 1931 | Box 16 \ 2 Scan031 | |
| Requesting information on radiator mounting, lubrication schemes, and speedometer drive designs. | 17th Aug 1931 | Box 16 \ 2 Scan032 | |
| Overheating issues and insufficient cooling margins on 40/50 HP models during road tests. | 1st Sep 1921 | Box 16 \ 2 Scan033 | |
| Instructions for modifying radiator hex-ended matrix tubes for 40/50 HP and 20/25 HP models. | 9th Sep 1931 | Box 16 \ 2 Scan034 | |
| Blueprints for a new Large Diameter American Type Matrix Tube for the Phantom II radiator. | 9th Sep 1931 | Box 16 \ 2 Scan035 | |
| Phantom II cooling tests, measuring the air temperature rise through the radiator and the effect of a louvred bonnet on under-bonnet air pressure. | 7th Sep 1931 | Box 16 \ 2 Scan036 | |
| Graph showing the rise of air temperature through a radiator matrix against road speed for chassis 19 EX. | 16th Sep 1931 | Box 16 \ 2 Scan037 | |
| Series of graphs plotting air pressure under the bonnet against road speed for different gears and bonnet types. | 16th Sep 1931 | Box 16 \ 2 Scan038 | |
| Cooling tests comparing air pressure under a bonnet fitted with flip-flap shutters versus a louvred bonnet. | 19th Sep 1931 | Box 16 \ 2 Scan039 | |
| Series of graphs showing air pressure under the bonnet at various road speeds for Chassis 20 EX under different configurations. | 16th Sep 1931 | Box 16 \ 2 Scan040 | |
| Mostly blank page with very faint, illegible text at the top and a date stamp at the bottom. | 19th Sep 1931 | Box 16 \ 2 Scan041 | |
| Cover note for an attached chart of top water and air temperatures on the 25-EX car in France. | 22th Sep 1931 | Box 16 \ 2 Scan042 | |
| Line graph comparing Kestrel & Condor engine oil temperature curves over several days in 1927. | 25th Oct 1927 | Box 16 \ 2 Scan043 | |
| Phantom II cooling tests comparing different hexagonal matrix radiator tubes and ventilation effects. | 1st Sep 1931 | Box 16 \ 2 Scan044 | |
| Uncomfortable air temperatures recorded near the pedals, necessitating improved ventilation. | 1st Sep 1931 | Box 16 \ 2 Scan045 | |
| Graph comparing air temperature rise during cooling tests with the bonnet on and off, using hexagonal matrix tubes. | 23th Sep 1931 | Box 16 \ 2 Scan046 | |
| Blank page with a date stamp. | 30th Sep 1931 | Box 16 \ 2 Scan047 | |
| Graph illustrating air temperature rise during cooling tests, comparing results with the bonnet on and off. | 23th Apr 1931 | Box 16 \ 2 Scan048 | |
| Issues and solutions for radiator mounting on the Phantom II with diamond engine mounting. | 22th Oct 1931 | Box 16 \ 2 Scan049 | |
| Standardisation of a radiator with .312' hexagon copper tubes for more efficient cooling. | 26th Sep 1931 | Box 16 \ 2 Scan050 | |
| Standardisation form for chassis parts detailing fitting information for a new part. | 11th Nov 1923 | Box 16 \ 2 Scan051 | |
| Issues with the Phantom II radiator suspension and diamond engine mounting. | 7th Nov 1931 | Box 16 \ 2 Scan052 | |
| Plunger modifications, frame deflection, and engine alignment issues causing a program delay. | 7th Nov 1931 | Box 16 \ 2 Scan053 | |
| Standardisation of chassis parts document for dropping the radiator 4 inches in the frame. | 20th Oct 1931 | Box 16 \ 2 Scan054 | |
| Standardisation form for a new chassis part, detailing its first fitment, testing, and associated costs. | 21th Sep 1931 | Box 16 \ 2 Scan055 | |
| Standardisation of the bottom water pipe from radiator to pump for the chassis. | 21th Sep 1931 | Box 16 \ 2 Scan056 | |
| 'Transmigration of Chassis Parts' form detailing the fitting of a new part onto the N.2 chassis series. | 2nd Feb 1932 | Box 16 \ 2 Scan057 | |
| Grease damaging the rubbers used in the Phantom II radiator control. | 2nd Feb 1932 | Box 16 \ 2 Scan058 | |
| Series of graphs comparing engine energy distribution, power, consumption, and heat loss at different compression ratios. | 5th Sep 1923 | Box 16 \ 2 Scan059 | |
| Proposing a modification to the fixing of the buffer flange on a centre-mounted radiator. | 1st Mar 1932 | Box 16 \ 2 Scan060 | |
| Solutions for radiator movement complaints on cars with centre-mounted radiators. | 21th Jun 1932 | Box 16 \ 2 Scan061 | |
| Procedures for adjusting radiator movement and resolving related issues. | 21th Jun 1932 | Box 16 \ 2 Scan062 | |
| Drawing and modification instructions for a Radiator Cross Member. | 22th Jun 1932 | Box 16 \ 2 Scan063 | |
| Need to increase initial radiator movement on P.2 and N.2 series cars. | 21th Mar 1932 | Box 16 \ 2 Scan064 | |
| Radiator movement, suggesting an alteration to the bottom tank and issuing a depot sheet for complaints. | 21th May 1932 | Box 16 \ 2 Scan065 | |
| Persistent issue of radiator wing movement and frame jellying, and proposed solutions. | 18th Aug 1932 | Box 16 \ 2 Scan066 | |
| Tests concerning the mounting of the radiator on the Phantom II engine. | 11th Aug 1932 | Box 16 \ 2 Scan067 | |
| Standardisation of a spring fitted to the thermostat of radiator shutters. | 11th Aug 1932 | Box 16 \ 2 Scan068 | |
| Introduction of a new part for a specific chassis series test. | 11th Oct 1932 | Box 16 \ 2 Scan069 | |
| Peculiar noise caused by the spring-loaded filler cap on radiators. | 17th Oct 1932 | Box 16 \ 2 Scan070 | |
| The use of a drawn tube radiator shutter on the 20/25 and Phantom chassis. | 4th Jan 1933 | Box 16 \ 2 Scan071 | |
| Standardisation of a soft copper washer to replace the rubber washer in the existing radiator cap. | 23th Sep 1932 | Box 16 \ 2 Scan072 | |
| Form concerning the standardisation of chassis parts, detailing implementation and costs. | 2nd Feb 1933 | Box 16 \ 2 Scan073 | |
| The trial and implementation of the Marston matrix radiator for 40/50 HP models. | 2nd Feb 1933 | Box 16 \ 2 Scan074 | |
| Technical specification and analysis of the radiator and shutters from a Morris Oxford car. | 8th Feb 1933 | Box 16 \ 2 Scan075 | |
| Blueprint detailing the specifications for Morris-Oxford radiator shutters. | 8th Feb 1934 | Box 16 \ 2 Scan076 | |
| Blueprint showing the plan and side view of the top of a shutter mechanism. | 8th Feb 1938 | Box 16 \ 2 Scan077 | |
| Modifying the 40/50 bumper chassis radiator to increase water flow for the P.2. model. | 13th Feb 1933 | Box 16 \ 2 Scan078 | |
| Agreement with Marstons regarding dimensional issues on Mark III radiators for the 40/50 car. | 12th Jul 1933 | Box 16 \ 2 Scan079 | |
| Confirming the use of springs with a 25 lbs load for the Centre Radiator Mounting on the Phantom II model. | 12th Oct 1933 | Box 16 \ 2 Scan080 | |
| Chasing a reply concerning radiator supplies for the 40/50 HP Long Type Chassis. | 5th Nov 1933 | Box 16 \ 2 Scan081 | |
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